Studies towards a postulated biomimetic Diels-Alder reaction for the synthesis of himgravine
作者:Jack E. Baldwin、Richard Chesworth、Jeremy S. Parker、Andrew T. Russell
DOI:10.1016/0040-4039(95)02045-4
日期:1995.12
The possible role of an iminium ion mediated Diels-Alder reaction on the biosynthetic pathway to himgravinc is discussed. The results of a preliminary investigation of a related oxycarbenium ion mediated Diels-Alder reaction are reported and are in accord with the stereochemistry of the natural product.
RETRACTED: Biomimetic approach to Galbulimina type I alkaloids
作者:Kirill Tchabanenko、Richard Chesworth、Jeremy S. Parker、Neel K. Anand、Andrew T. Russell、Robert M. Adlington、Jack E. Baldwin
DOI:10.1016/j.tet.2005.09.050
日期:2005.12
On treatment with trifluoroacetic acid the tetraene precursor 23 underwent Boc deprotection, condensation and an iminium ion accelerated intramolecular Diels-Alder cycloaddition resulting in an iminium species 12, which was further converted into himbacine 1, himbeline 3 and himandravine 4, three out of four Galbulimina type I alkaloids thus providing strong evidence for the proposed biogenesis of this important family of alkaloids. (c) 2005 Elsevier Ltd. All rights reserved.